package com.yunhaikeji.core.util;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;

public class AESUtil {

    private String password = "46CC1C4D1C474A8029EAB203541510";

    private static final String KEY_ALGORITHM = "AES";
    private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";//默认的加密算法

    /**
     * AES 加密操作
     *
     * @param content 待加密内容
     * @return 返回16进制加密数据
     */
    public String encrypt(String content) {
        try {
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 创建密码器

            byte[] byteContent = content.getBytes(StandardCharsets.UTF_8);

            cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(password));// 初始化为加密模式的密码器

            byte[] result = cipher.doFinal(content.getBytes());// 加密

            return new String(Base64.getEncoder().encode(result), StandardCharsets.UTF_8);
        } catch (Exception ex) {
        }

        return null;
    }


    /**
     * AES 解密操作
     *
     * @param content
     * @return
     */
    public String decrypt(String content) {

        try {
            //实例化
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

            //使用密钥初始化，设置为解密模式
            cipher.init(Cipher.DECRYPT_MODE, getSecretKey(password));

            //执行操作
            byte[] result = cipher.doFinal(parseHexStr2Byte(content));

            return new String(result, "utf-8");
        } catch (Exception ex) {
        }

        return null;
    }

    /**
     * 生成加密秘钥
     *
     * @return
     * @throws UnsupportedEncodingException
     */
    private SecretKeySpec getSecretKey(final String password) throws UnsupportedEncodingException {
        //返回生成指定算法密钥生成器的 KeyGenerator 对象
        KeyGenerator kg = null;

        try {
            KeyGenerator _generator = KeyGenerator.getInstance( KEY_ALGORITHM );
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
            secureRandom.setSeed(password.getBytes("UTF-8"));
            _generator.init(128,secureRandom);
            //生成一个密钥
            SecretKey secretKey = _generator.generateKey();
            SecretKeySpec sks = new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);// 转换为AES专用密钥
            return sks;

        } catch (NoSuchAlgorithmException ex) {
        }

        return null;
    }

    /**2进制转化成16进制
     * @param buf
     * @return
     */
    private String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**将16进制转换为二进制
     * @param hexStr
     * @return
     */
    private byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length()/2];
        for (int i = 0;i< hexStr.length()/2; i++) {
            int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
            int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

    public static void main(String[] args) throws Exception {
        String content = "22010619007200220";
        System.out.println("加密前：" + content);
        AESUtil util = new AESUtil(); // 密钥
        System.out.println("加密后:"+util.encrypt(content)); // 加密



    }
}
